399: Femoral Nerve Block for Pain Management of Hip Fractures in the Emergency Department: Preliminary Results of a Randomized, Controlled Trial

Peripheral nerve blocks for hip fractures in adults

BACKGROUND

This review was published originally in 1999 and was updated in 2001, 2002, 2009, 2017, and 2020. Updating was deemed necessary due to the high incidence of hip fractures, the large number of official societies providing recommendations on this condition, the possibility that perioperative peripheral nerve blocks (PNBs) may improve patient outcomes, and the major role that PNBs may play in reducing preoperative and postoperative opioid use for analgesia.

OBJECTIVES

To compare PNBs used as preoperative analgesia, as postoperative analgesia, or as a supplement to general anaesthesia versus no nerve block (or sham block) for adults with hip fracture. Outcomes were pain on movement at 30 minutes after block placement, acute confusional state, myocardial infarction, chest infection, death, time to first mobilization, and costs of an analgesic regimen for single-injection blocks. We undertook the update to look for new studies and to update the methods to reflect Cochrane standards.

SEARCH METHODS

For the updated review, we searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 11), in the Cochrane Library; MEDLINE (Ovid SP, 1966 to November 2019); Embase (Ovid SP, 1974 to November 2019); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO, 1982 to November 2019), as well as trial registers and reference lists of relevant articles.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) assessing use of PNBs compared with no nerve block (or sham block) as part of the care provided for adults 16 years of age and older with hip fracture.  DATA COLLECTION AND ANALYSIS: Two review authors independently screened new trials for inclusion, assessed trial quality using the Cochrane Risk of Bias-2 tool, and extracted data. When appropriate, we pooled results of outcome measures. We rated the certainty of evidence using the GRADE approach.

MAIN RESULTS

We included 49 trials (3061 participants; 1553 randomized to PNBs and 1508 to no nerve block (or sham block)). For this update, we added 18 new trials. Trials were published from 1981 to 2020. Trialists followed participants for periods ranging from 5 minutes to 12 months. The average age of participants ranged from 59 to 89 years. People with dementia were often excluded from the included trials. Additional analgesia was available for all participants. Results of 11 trials with 503 participants show that PNBs reduced pain on movement within 30 minutes of block placement (standardized mean difference (SMD) -1.05, 95% confidence interval (CI) -1.25 to -0.86; equivalent to -2.5 on a scale from 0 to 10; high-certainty evidence). Effect size was proportionate to the concentration of local anaesthetic used (P = 0.0003). Based on 13 trials with 1072 participants, PNBs reduce the risk of acute confusional state (risk ratio (RR) 0.67, 95% CI 0.50 to 0.90; number needed to treat for an additional beneficial outcome (NNTB) 12, 95% CI 7 to 47; high-certainty evidence). For myocardial infarction, there were no events in one trial with 31 participants (RR not estimable; low-certainty evidence). From three trials with 131 participants, PNBs probably reduce the risk for chest infection (RR 0.41, 95% CI 0.19 to 0.89; NNTB 7, 95% CI 5 to 72; moderate-certainty evidence). Based on 11 trials with 617 participants, the effects of PNBs on mortality within six months are uncertain due to very serious imprecision (RR 0.87, 95% CI 0.47 to 1.60; low-certainty evidence). From three trials with 208 participants, PNBs likely reduce time to first mobilization (mean difference (MD) -10.80 hours, 95% CI -12.83 to -8.77 hours; moderate-certainty evidence). One trial with 75 participants indicated there may be a small reduction in the cost of analgesic drugs with a single-injection PNB (MD -4.40 euros, 95% CI -4.84 to -3.96 euros; low-certainty evidence). We identified 29 ongoing trials, of which 15 were first posted or at least were last updated after 1 January 2018.  AUTHORS' CONCLUSIONS: PNBs reduce pain on movement within 30 minutes after block placement, risk of acute confusional state, and probably also reduce the risk of chest infection and time to first mobilization. There may be a small reduction in the cost of analgesic drugs for single-injection PNB. We did not find a difference for myocardial infarction and mortality, but the numbers of participants included for these two outcomes were insufficient. Although randomized clinical trials may not be the best way to establish risks associated with an intervention, our review confirms low risks of permanent injury associated with PNBs, as found by others. Some trials are ongoing, but it is unclear whether any further RCTs should be registered, given the benefits found. Good-quality non-randomized trials with appropriate sample size may help to clarify the potential effects of PNBs on myocardial infarction and mortality.

Peripheral nerve blocks for hip fractures

BACKGROUND

Various nerve blocks with local anaesthetic agents have been used to reduce pain after hip fracture and subsequent surgery. This review was published originally in 1999 and was updated in 2001, 2002, 2009 and 2017.

OBJECTIVES

This review focuses on the use of peripheral nerves blocks as preoperative analgesia, as postoperative analgesia or as a supplement to general anaesthesia for hip fracture surgery. We undertook the update to look for new studies and to update the methods to reflect Cochrane standards.

SEARCH METHODS

For the updated review, we searched the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), MEDLINE (Ovid SP, 1966 to August week 1 2016), Embase (Ovid SP, 1988 to 2016 August week 1) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO, 1982 to August week 1 2016), as well as trial registers and reference lists of relevant articles.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) involving use of nerve blocks as part of the care provided for adults aged 16 years and older with hip fracture.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed new trials for inclusion, determined trial quality using the Cochrane tool and extracted data. When appropriate, we pooled results of outcome measures. We rated the quality of evidence according to the GRADE Working Group approach.

MAIN RESULTS

We included 31 trials (1760 participants; 897 randomized to peripheral nerve blocks and 863 to no regional blockade). Results of eight trials with 373 participants show that peripheral nerve blocks reduced pain on movement within 30 minutes of block placement (standardized mean difference (SMD) -1.41, 95% confidence interval (CI) -2.14 to -0.67; equivalent to -3.4 on a scale from 0 to 10; I² = 90%; high quality of evidence). Effect size was proportionate to the concentration of local anaesthetic used (P < 0.00001). Based on seven trials with 676 participants, we did not find a difference in the risk of acute confusional state (risk ratio (RR) 0.69, 95% CI 0.38 to 1.27; I² = 48%; very low quality of evidence). Three trials with 131 participants reported decreased risk for pneumonia (RR 0.41, 95% CI 0.19 to 0.89; I² = 3%; number needed to treat for an additional beneficial outcome (NNTB) 7, 95% CI 5 to 72; moderate quality of evidence). We did not find a difference in risk of myocardial ischaemia or death within six months, but the number of participants included was well below the optimal information size for these two outcomes. Two trials with 155 participants reported that peripheral nerve blocks also reduced time to first mobilization after surgery (mean difference -11.25 hours, 95% CI -14.34 to -8.15 hours; I² = 52%; moderate quality of evidence). One trial with 75 participants indicated that the cost of analgesic drugs was lower when they were given as a single shot block (SMD -3.48, 95% CI -4.23 to -2.74; moderate quality of evidence).

AUTHORS' CONCLUSIONS

High-quality evidence shows that regional blockade reduces pain on movement within 30 minutes after block placement. Moderate-quality evidence shows reduced risk for pneumonia, decreased time to first mobilization and cost reduction of the analgesic regimen (single shot blocks).

Use of Femoral Nerve Blocks to Manage Hip Fracture Pain among Older Adults in the Emergency Department: A Systematic Review

Objective

Hip fractures are a common source of acute pain amongst the frail elderly. One potential technique to adequately manage pain in this population is the femoral nerve block. The objective of this systematic review was to provide updated evidence for the use of femoral nerve blocks as a pain management technique for older hip fracture patients in the emergency department (ED).

Data Sources

Searches of Medline, EMBASE, and the Cochrane Central Register of Controlled Trials were conducted between December 2010 and May 2014. The reference list of a previous systematic review was also searched.

Study Selection

We included randomized control trials examining the use of femoral nerve blocks in the ED among older adults (65 years of age or older) with acute hip fracture.

Data Extraction

Among 93 citations reviewed, seven trials were included. Four studies employed a single femoral nerve block, while three studies employed continuous (catheter-placed) femoral blocks. All but one of the studies were found to have a high risk of bias.

Data Synthesis

All studies reported reductions in pain intensity with femoral nerve blocks. All but one study reported decreased rescue analgesia requirements. There were no adverse effects found to be associated with the femoral block procedure; rather, two studies found a decreased risk of adverse events such as respiratory and cardiac complications.

Conclusions

Femoral nerve blocks appear to have benefits both in terms of decreasing the pain experienced by older patients, as well as limiting the amount of systemic opioids administered to this population.

Efficacy of supplemental peripheral nerve blockade for hip fracture surgery: multiple treatment comparison

PURPOSE

This study was designed to determine the most effective peripheral nerve block supplement to standard anesthesia management for hip fracture patients.

METHODS

We systematically reviewed randomized controlled trials (RCTs) published from 1990 to 2010 and conducted multiple treatment comparisons using direct and indirect evidence for two outcomes, i.e., acute pain intensity and delirium. We combined trials by type of injection (regardless of time of insertion during the perioperative phase, use of nerve block catheter, local anesthetic type, additives, or duration of treatment).

RESULTS

Twenty-one RCTs comprising 1,422 participants were included. In most cases, the trials were conducted in Europe; they excluded patients with cognitive impairment, and they were unclear or at high risk of bias. The combination of obturator and lateral femoral cutaneous nerve blockade had the highest probability of being the most effective against acute postoperative pain. Fascia iliaca blockade had the highest probability of being the most effective against delirium. There was no difference in outcomes among other nerve blocks.

CONCLUSION

Not all nerve blocks are equally effective in improving outcomes after hip fracture. Multiple treatment comparison, a tool to compare the effectiveness of multiple treatments simultaneously, provides useful guidance to anesthesia providers seeking effective treatment when faced with a body of RCTs wherein each investigates one treatment. More RCTs comparing multiple nerve blocks in hip fracture are needed.